Jaskier: instinctively protects yen
Geralt: knows he doesn't have to protect yen but now has to step forward to protect them both as jaskier CANNOT fight a fucking monster
Yennefer: moving from behind them to Geralt's side, (those men just keep blocking my fucking sight, should have just made myself 8 feet tall during the transformation)
Jaskier: ah, oh, yeah, right, I'll just, eh, be your solid backing, don't worry your backs are safe with me... hey Roach how's it going
THE interesting chemistry between geraskefer is that jaskier subconsciously, instinctively would treat a lady he loves (any lady he loves) with care and protection. Like in season one E4 he was literally protecting a random lady that the storm accidentally threw in his arms the second he saw her. The reason that he didn't do that with yen in S1 is because he was straight out hostile and treating her as not only an enemy but an enemy that might hurt Geralt.
In S2 that changed so we can see it happen all over the place. Him trying to protect yen is just, so, so adorable. Even without magic, she still has fighting skills and, fuck, Yen can literally aim with a fucking axe, she managed to chop the chains without hurting the person wearing them, anyone who's ever used a long axe, would know how much strength and control that fucking takes. That is SKILL not just muscles.
Meanwhile Geralt, instinctively protects jaskier, as he's used to jaskier running to him with danger behind (monster or just some man at the bar) from years of traveling together.
And yennefer, just being YENNEFER
I jus can't get enough of this